More than 200 million years ago in what's now southern Utah, crocodile-like creatures called phytosaurs roamed the landscape. Now, their fossilized skeletons have been found—on land that fell within the original boundaries of Bears Ears National Monument, before the Trump administration shrunk the monument by nearly 85 percent.

The fossil fragments include three toothy, long-snouted phytosaur skulls. It turns out that the site had been looted before paleontologists got to it—but some scientific sleuthing by researchers, led by Museums of Western Colorado paleontologist Robert Gay, let them track down a missing skull fragment that had been poached.

“Based on our small, initial excavation, we believe that this 63-meter site may be the densest area of Triassic period fossils in the nation, maybe the world,” said Gay in a statement prepared by the Wilderness Society. “If this site can be fully excavated, it is likely that we will find many other intact specimens, and quite possibly even new vertebrate species.”

Learn About Bears Ears When the Monument Was Made

“Within the paleontology community, the size of this site and the potentially large number of specimens buried there represent an extraordinary opportunity to expand our knowledge of species that lived during the Triassic period,” added Tracy J. Thomson, coordinator of the WAVP conference, in a statement.

“There is an incredible amount of work yet to be done, and we hope that paleontological sites like this one will get the protection they need before more of our prehistoric past is forever lost to looting or irreplaceably damaged by mining in the region.”

Bones to Pick With Trump

Gay's announcement, made at the Western Association of Vertebrate Paleontologists's annual conference in St. George, Utah, also calls attention to President Trump's downsizing of Utah's Bears Ears and Grand Staircase Escalante national monuments.

Utah state officials and mining interests applauded the president's move, saying it restored local control over the state's mineral resources. However, conservation groups, Native American tribes, and scientists have decried the decision. As National Geographic has previously reported, the monument originally encompassed 1.35 million acres, protecting cliff dwellings, one of the western U.S.'s largest collections of tribal artifacts, and lands rich with ancient fossils.

Fossils on BLM land are still partially protected. Under a law passed in 2009, it's illegal to collect vertebrate fossils on federal lands without a scientific permit. But removing the lands' monument status could spell trouble for fossils, nonetheless.

This designation aims to protect natural and cultural heritage while also permitting economic use. Paleontologists fear that industrial activities like coal mining could outweigh their concerns, leading to the destruction of scientifically invaluable fossils.

“Often a vertebrate fossil is one of its kind. But even when it’s not one of its kind, paleontologists need to know things about ranges of variation, geographic distributions of species, and so on,” said Polly, the president of the Society of Vertebrate Paleontology (SVP), to ScienceInsider. “So from the society’s point of view, unless vertebrate fossils are just complete scrap that you can’t identify, they're scientifically important.”